The present invention describes a new and improved elevator door guide, which guides the doors of an elevator cab, or the corridor doors that open at each floor served by the elevator, along a groove found in the sill of the door opening.
An elevator system is comprised of a vertical shaft and an elevator cab that moves up and down the shaft as it transports people and things between floors. An elevator contains door (s) for the elevator cab and door (s) located at each floor served by the elevator known as corridor doors. The method of installing both cab and corridor doors is similar. Generally, door sills are provided at the respective door opening on which struts are mounted. These struts support “headers”. In turn, the headers support the door hanger tracks/rails on which the entrance door panels are hung, thus bearing the bulk of the weight of the door (s). The bottom of the door (s) is then guided by the use of door guides which ride in the groove of the door sill, with the elevator door guide secured to the door at the bottom.
An elevator door guide does not usually come in contact with bottom of the groove in the door sill, but uses the sides of the groove to keep the door moving longitudinally along the groove, as the doors open and close.
Although lateral movement of the door is required for the removability of the doors for maintenance, it creates an undesirable risk of the door suddenly swinging inwardly during its normal elevator operation due to lateral forces imposed onto the door, thus causing a serious risk of injury or death when a person falls into the elevator shaft. Accidents have been known to happen where the elevator door guide disintegrates, or otherwise fail due to loads imposed on them from people leaning on doors, running into doors or even from wheel chairs hitting doors. Since the guide is hidden from view and is not needed to keep a door hanging in its place, an onlooker is unaware that the guide may be missing or has been compromised and may lean on the elevator doors. Without a guide, the door will swing into the elevator shaft, causing a person who leaned on them to fall to his or her detriment or death. A compromised guide could lead to the same result.
Although elevator door guides are well known, nothing in the prior art addresses this safety risk adequately. Prior inventions deal with innovative ways of how an elevator door can be guided longitudinally within a groove, but fail to provide any back-up components or strength members to ensure that the door would not swing freely into the elevator shaft if the guide is compromised.
For example, U.S. Pat. No. 5,174,675 (1992) to Martin discloses a guide that has only several screws keeping it in place. The guide is not made of metal and thus can fail under strong lateral pressure. The safety tabs designed to keep the door from swinging inwardly do not achieve the desired protection. First, these tabs are above the edge of the groove and assume that the guide will disintegrate, causing the door to sink into the groove. This may happen in case of a fire, which is the main focus of '675 patent. However, in most cases the guide failed due to the lateral pressure exerted on the doors, for example by those leaning or running into the doors. A failure of this kind may keep the guide in place, but will make it cracked or bent. This creates a situation where the safety tabs have not yet engaged the groove, when the guide is already decisively compromised.
Similarly, a U.S. Pat. No. 5,706,913 to Rivera (1998) discloses another type of guide. This one is a narrow metal sliver that guides the doors along a groove located within the outer edge of the door sill. Nothing is reinforcing this sliver of a guide against a potential failure.
On the other hand, the present invention adds improved safety features which are highly desirable and much needed in the industry.